[net] net: dsa: tag_rtl4_a: fix egress tags
diff mbox series

Message ID 20210228170823.1488-1-dqfext@gmail.com
State Accepted
Commit 9eb8bc593a5eed167dac2029abef343854c5ba75
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Series
  • [net] net: dsa: tag_rtl4_a: fix egress tags
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Commit Message

DENG Qingfang Feb. 28, 2021, 5:08 p.m. UTC
Commit 86dd9868b878 has several issues, but was accepted too soon
before anyone could take a look.

- Double free. dsa_slave_xmit() will free the skb if the xmit function
  returns NULL, but the skb is already freed by eth_skb_pad(). Use
  __skb_put_padto() to avoid that.
- Unnecessary allocation. It has been done by DSA core since commit
  a3b0b6479700.
- A u16 pointer points to skb data. It should be __be16 for network
  byte order.
- Typo in comments. "numer" -> "number".

Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
---
 net/dsa/tag_rtl4_a.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Comments

Florian Fainelli Feb. 28, 2021, 5:54 p.m. UTC | #1
On 2/28/2021 9:08 AM, DENG Qingfang wrote:
> Commit 86dd9868b878 has several issues, but was accepted too soon
> before anyone could take a look.
> 
> - Double free. dsa_slave_xmit() will free the skb if the xmit function
>   returns NULL, but the skb is already freed by eth_skb_pad(). Use
>   __skb_put_padto() to avoid that.
> - Unnecessary allocation. It has been done by DSA core since commit
>   a3b0b6479700.
> - A u16 pointer points to skb data. It should be __be16 for network
>   byte order.
> - Typo in comments. "numer" -> "number".
> 
> Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags")
> Signed-off-by: DENG Qingfang <dqfext@gmail.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Linus Walleij March 1, 2021, 1:58 p.m. UTC | #2
On Sun, Feb 28, 2021 at 6:08 PM DENG Qingfang <dqfext@gmail.com> wrote:

> Commit 86dd9868b878 has several issues, but was accepted too soon
> before anyone could take a look.
>
> - Double free. dsa_slave_xmit() will free the skb if the xmit function
>   returns NULL, but the skb is already freed by eth_skb_pad(). Use
>   __skb_put_padto() to avoid that.
> - Unnecessary allocation. It has been done by DSA core since commit
>   a3b0b6479700.
> - A u16 pointer points to skb data. It should be __be16 for network
>   byte order.
> - Typo in comments. "numer" -> "number".
>
> Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags")
> Signed-off-by: DENG Qingfang <dqfext@gmail.com>

Ooops I send patches before properly going through the mailbox.
Oh well things like that happen.

David: ignore my patches to the same tagger and apply this instead!

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
Vladimir Oltean March 1, 2021, 2:01 p.m. UTC | #3
On Mon, Mar 01, 2021 at 02:58:59PM +0100, Linus Walleij wrote:
> On Sun, Feb 28, 2021 at 6:08 PM DENG Qingfang <dqfext@gmail.com> wrote:
> 
> > Commit 86dd9868b878 has several issues, but was accepted too soon
> > before anyone could take a look.
> >
> > - Double free. dsa_slave_xmit() will free the skb if the xmit function
> >   returns NULL, but the skb is already freed by eth_skb_pad(). Use
> >   __skb_put_padto() to avoid that.
> > - Unnecessary allocation. It has been done by DSA core since commit
> >   a3b0b6479700.
> > - A u16 pointer points to skb data. It should be __be16 for network
> >   byte order.
> > - Typo in comments. "numer" -> "number".
> >
> > Fixes: 86dd9868b878 ("net: dsa: tag_rtl4_a: Support also egress tags")
> > Signed-off-by: DENG Qingfang <dqfext@gmail.com>
> 
> Ooops I send patches before properly going through the mailbox.
> Oh well things like that happen.
> 
> David: ignore my patches to the same tagger and apply this instead!
> 
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> 
> Yours,
> Linus Walleij

Last time I checked, performance/timing sensitive code is impacted by
netdev_dbg calls even if dynamic debugging isn't turned on. However,
neither your patches nor Qingfang's have removed that netdev_dbg line.
Is there any good reason to keep it?

Patch
diff mbox series

diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c
index c17d39b4a1a0..e9176475bac8 100644
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -35,14 +35,12 @@  static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 				      struct net_device *dev)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
+	__be16 *p;
 	u8 *tag;
-	u16 *p;
 	u16 out;
 
 	/* Pad out to at least 60 bytes */
-	if (unlikely(eth_skb_pad(skb)))
-		return NULL;
-	if (skb_cow_head(skb, RTL4_A_HDR_LEN) < 0)
+	if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false)))
 		return NULL;
 
 	netdev_dbg(dev, "add realtek tag to package to port %d\n",
@@ -53,13 +51,13 @@  static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 	tag = skb->data + 2 * ETH_ALEN;
 
 	/* Set Ethertype */
-	p = (u16 *)tag;
+	p = (__be16 *)tag;
 	*p = htons(RTL4_A_ETHERTYPE);
 
 	out = (RTL4_A_PROTOCOL_RTL8366RB << 12) | (2 << 8);
-	/* The lower bits is the port numer */
+	/* The lower bits is the port number */
 	out |= (u8)dp->index;
-	p = (u16 *)(tag + 2);
+	p = (__be16 *)(tag + 2);
 	*p = htons(out);
 
 	return skb;